10. Trebuchet

Siege warfare was one of the most enduring types of warfare, from simple hill forts to imposing stone citadels. Often, the campaigns waged against these structures lasted for months, as the besieged sat behind almost impenetrable walls and moats. The trebuchet completely altered the balance of siege warfare. Firing much bigger projectiles (at much greater distance), and much more accurately than traditional catapults, trebuchets were capable of destroying a stone wall in a matter of days, dramatically improving the chances of a besieging force capturing a city before a relief force could arrive, or their camp was destroyed by disease.